When a person calls a phone and then hangs up before the other person gets a chance to answer it. It's like the classic game of ding dong ditch, only with a phone. For an aggressive phone war, you can call and hang up quickly resulting in a half-ring, and you can do so multiple times in succession. You can also call phones for people who are absent just to aggravate people who sit nearby. This is especially amusing if the volume is cranked way up and you pretend that the phone is malfunctioning.

The bald guy got really ticked off and talked to our boss about the phone wars.